This standard specifies the Hall test method for electroplating solutions. This standard is applicable to the determination of the cathode current density range, dispersibility and leveling properties of electroplating solutions, and is also applicable to the study of the influence of changes in the composition and process conditions of electroplating solutions on the quality of the coating. JB/T 7704.1-1995 Electroplating solution test method Hall slot test JB/T7704.1-1995 Standard download decompression password: www.bzxz.net
This standard specifies the Hall test method for electroplating solutions. This standard is applicable to the determination of the cathode current density range, dispersibility and leveling properties of electroplating solutions, and is also applicable to the study of the influence of changes in the composition and process conditions of electroplating solutions on the quality of the coating.

Mechanical Industry Standard of the People's Republic of China
Test Methods for Electroplating Solutions
Hall Cell Test
1 Subject Content and Scope of Application
This standard specifies the Hall Cell Test Method for Electroplating Solutions. JB/T 7704.1-95
This standard is applicable to the determination of the cathode current density range, dispersion ability and leveling properties of the electroplating solution, and is also applicable to the study of the influence of changes in the composition of the electroplating solution and process conditions on the quality of the coating. 2 Terminology
Hall Cell: A trapezoidal plating cell for non-conductive materials, in which the arrangement of the electrodes enables the observation of the cathode or anode effect in a wide current density range.
3 Principle of the Method
The principle that the distance between the cathode and the anode in the Hall Cell is different and the corresponding current density is also different is used to test the performance of the electroplating solution and the factors affecting the quality of the coating.
4 Test Apparatus, Instruments and Equipment
4.1 Test Apparatus
The Hall Cell Test Apparatus is shown in Figure 1.
Figure 1 Hall cell test device
DC power supply; 2-Ammeter; 3-Yonger cell: 4-Cathode: 5-Anode 4.2 Test instruments and equipment
4.2.1 Hall cell
Hall cell is a small trapezoidal electroplating cell. Its basic structure is shown in Figure 2. The cell body is generally made of acid-resistant and alkali-resistant insulating materials. The most important feature of the Hall cell is that the cathode and anode are not parallel and maintain a certain angle. According to the volume of the solution, it can be divided into three types of Hall cells: 250mL, 500mL, and 1000mL. The most commonly used are 250mL and 1000ml. The internal dimensions of the bottle body are listed in Table 1. Approved by the Ministry of Machinery Industry on June 20, 1995
Implemented on January 1, 1996bzxZ.net
Volume of Hall cell mL
1000
JB/T 7704. 1 -- 95
Figure 2 Basic structure of Hall cell
Table 1
Internal dimensions of Hall cell
In practical applications, a commercially available Hall cell has a heating tube installed on the d side and a row of air stirring holes opened next to the cathode. It is widely used. There is also an improved Hall cell (see Figure 3), which has the same shape and size as the ordinary Hall cell, but only 6 holes are drilled in the long wall of the two parallel walls of the cell and 4 holes are drilled in the short wall. There is no strict requirement for the position and size of the holes. The advantage of this cell is that it is placed in another larger container containing the plating solution to be tested that can be heated (or cooled). Thus, the required more stable plating solution composition and liquid temperature are obtained. Figure 3 Improved Hall Trough
4.2.2 Anode
The anode material is the same as that used in production and meets the national standards for electroplating anodes. The specific dimensions are shown in Table 2. The anode is in the shape of a flat plate. In the plating solution that easily passivates the anode, a corrugated or mesh shape can be used, and its geometric thickness cannot exceed 5mm. 4.2.3 Cathode
The cathode material should be selected according to the test conditions. Generally, 0.2-1mm thick brass plates or steel plates are used. The use of other materials should have little effect on the test process. The test piece can be ground, etched or polished according to the test purpose, and then the back is coated with insulating paint and dried. Its specific dimensions are shown in Table 2.
Table 2 Hall cell cathode and anode dimensions
Hall cell type
250mL
1000mL
4.2.4 Power supply
Cathode dimensions
100×70
125×90
The power supply should be relatively stable, and it is best to use a DC constant current power supply. 4.2.5 DC ammeter
Range: 0~10A.0.5 level or 1 level.
In actual testing. A complete set of Hall cell test equipment with heating and stirring functions can be used. 2
Anode size
64×70
85×90
5 Selection of test conditions
5.1 Plating solution
JB/T 7704.1-95
In order to obtain correct test results, the test plating solution should be representative. When repeating the test, the volume of plating solution taken for each test should be the same. When using an insoluble anode, the solution should be replaced after 1 to 2 electroplating tests. If a soluble anode is used, the solution should be replaced after 4 to 5 tests. When testing the influence of trace impurities or additives, the number of tests per tank solution should be reduced as appropriate. 5.2 Current intensity
The current intensity should be selected according to the properties of the plated substrate. If the upper limit of the current intensity allowed by the plating solution is large, the current intensity during the test should be larger, but usually between 0.5 and 3A. For some plating types such as chromium plating solutions, it can be increased to 5 to 10A. When testing the influence of trace impurities, 0.5~1A can be used.
5.3 Test time
The time of the Hall slot test should be determined according to the test, generally 5~10min. 5.4 Test temperature
The temperature of the Hall slot test should be determined according to the properties of the plating solution and the purpose of the test. 6 Test steps
6.1 Pour the solution to be tested into the Hall slot, and insert the cleaned anode plate against the side of the slot wall. 6.2 Install the wiring as shown in Figure 1, and keep the plating solution at a constant temperature according to the process conditions. 6.3 Place the cathode that meets the requirements of electroplating pretreatment close to the side of the slot wall and charge it into the slot. According to the process conditions of the plating wave, control the current intensity and electroplating time for electroplating.
6.4 Disconnect the power supply. Take out the cathode test piece, wash it, and dry it. Process the results according to the test purpose. 7 The result shows that the current density is the smallest. As the distance between the cathode and the anode decreases, the current density of each part of the cathode increases. 7.1 Calculation of the current density of each part of the cathode
In the Hall cell, the distance from each part of the cathode to the anode is different, and the current density of each part is also different. The current density is the smallest at the end far from the anode (called the far end). As the distance between the cathode and the anode decreases, the current density gradually increases until the end close to the anode (called the near end), the current density is the largest. The current density of each part on the cathode can be calculated using the following empirical formula: D = I(C - C,logL)
Where: L is the distance from a certain part of the cathode to the near end of the cathode, cm; I is the current intensity during the test, A:
Dk is the corresponding current density of a certain part on the cathode, A/m (A/dm); constants related to the properties of the plating solution.
For reference, for a 250mL Hall cell, C,=5.10.Cz=5.24 can be taken; for a 1000mL Hall cell, C-3.26, C2-3.04 can be taken. The approximate value of the current density is calculated by the above formula. In addition, since the error of the current density calculated near the two ends of the cathode is large, it is generally recommended to take the value more than one centimeter away from the two ends. In practice, for convenient observation, the "Hall cell test sample current density scale" can be drawn according to formula (1) to directly measure the current density value of a certain part on the Hall cell test piece.
7.2 Method for indicating the appearance of the cathode test piece coating
In order to correctly evaluate the Hall cell test results. Generally, a section of the cathode sample coating 10mm above the horizontal midline (see Figure 4) is selected as the test result to evaluate the coating quality and the symbols shown in Figure 5 are used to represent the appearance of the coating. Some representative test pieces can be coated with varnish and kept for reference.
8 Test report
Bright
Semi-bright
JB/T 7704.1-95
Liquid surface
Figure 4 Cathode test result Location selection (250mL tank) Male
Strip
Burning or rough
Dendrite or powder
Blistering
Pinhole or pitting
Figure 5 Symbols for coating appearance
The test report should generally include the following: a.
Name and model of the tested plating solution;
This standard number:
Test instruments and equipment;
Test conditions;
Test results and calculation formulas;
Test date and test personnel.
Additional remarks:
This standard is proposed by the National Metal and Non-metal Covering Standardization Committee. This standard is under the jurisdiction and drafting responsibility of the Wuhan Materials Protection Research Institute of the Ministry of Machinery Industry. The main drafter of this standard is Jiang Xinhua.
Brittle or cracked
Bottom exposed
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